My local DNS server setup

As part of my recent obsession with self-hosting all the things, I set up a DNS server on my home server box. Initially, I used DNSmasq but that turned out to be extremely unreliable. Now I am running CoreDNS, based on the AdGuard DNS server which essentially packages up some useful plugins for CoreDNS into one binary. This is how I did it.

Documentation for running the AdGuard DNS plugin is non-existent so some of these steps required reading the Go source code itself to work out. The systemd configuration is in a separate repository, which was handy for my purposes.

The CoreDNS binary needs to be compiled. The AdGuard DNS repository has most of the requirements automated, but it did need some customisations. Check out my fork for the small changes. A working Golang install is also needed; I used Go 1.10. This was done from my Ubuntu 18.04 WSL environment.

git clone [email protected]:sbreatnach/AdGuardDNS.git
cd AdGuard
version=custom make build

My local home server box hosts the DNS server for my entire home network. It’s a standard Ubuntu 16.04 box, the same one I used for setting up Sandstorm, as described previously.

scp go_custom/bin/coredns

All the following was run from the server box. All commands are run as root:

adduser coredns
mkdir /etc/coredns
mkdir /var/lib/coredns
cat <<EOF >> /etc/coredns/hosts   nas.home
wget -O /etc/coredns/filters.txt
cat <<EOF >> /etc/coredns/Corefile
. {
    rewrite name regex (.*)\.nas\.home nas.home
    proxy .
    dnsfilter {
        filter 15 /etc/coredns/filters.txt
    hosts /etc/coredns/hosts {
chown -R coredns:coredns /etc/coredns
chown -R coredns:coredns /var/lib/coredns
git clone ~/coredns-deployment
cp ~/coredns /usr/bin/adguard-coredns
cp ~/coredns-deployment/systemd/coredns.service /etc/systemd/system/
setcap CAP_NET_BIND_SERVICE=+eip /usr/bin/adguard-coredns
systemctl daemon-reload
systemctl enable coredns.service

Note that this retains the wildcard DNS matching required for Sandstorm.

Once this is all done, the DNS server should respond correctly to dig invocations and block all filtered domains:

dig @
dig @ nas.home
dig @ random.nas.home

And that’s it! I do enjoy seeing this stuff come together, gives me nice fuzzy feelings :)

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